Method of utilizing iron, blast-furnace, flue-dust.



R. BAGG'ALEY'. METHOD OF UTILIZING IRON, BLAST FUR-NAOE, FLUE DUST.

. APPLICATION FIL ED JULY 24, 1 913. V

Patented-Dec. 16, 1913.

T T I (a INVEIO: I

M. WQQM';

WlTN ESSES RALPH BAGGALEY, or PITTSBURGH, PENNSYLVANIA.

METHOD OF UTILIZING IRON, BLAST-FURNACE, FLUE-DUST.

To all whom it may con'cem:

' Be it known that I, RAlZ-Pl-I BAGGALEY, a f

citizen of the Un ited' -States, residing at Pittsburgh, Allegheny county, Pennsylvania, have invented a new and useful Method of Utilizing Iron, Blast-Furnace, Flue-Dust, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figures 1 and 2 are vertical sectional views illustrating different forms of apparatus which may be used for carrying outmy novel method.

My invention has relation to a new and useful method of utilizing the flue'dustand' fines from iron-blast-furnace's, and also to the novel product obtained by such method. In modern iron-blast-furnace practice, a very high blast pressure is used, andmany oft-he ores employed ,are'very friable. In 4 the operation of the furnaces thereis a heavy production of fines and flue dust. It. has been estimated that every ton ofiron'or'e smelted yields about eighty pounds of flue dust, or approximately four per cent. Thus, a blast furnace which'smelts 1,000 tons of ore. per day produces about 40 tons of this flue dust, which upon an average contains about four'doll'ars .of iron' per ton.- For many years, this material waswastefully thrown overt-he dumps, or used as a fillingor grad-- ing. material. More recently, however, it has been placed in stock piles in the hope that some eilicient and economical method of its utilization might be developed. In the Pittsburgh district alone, it is estimated that an accumulation of this material amounts to. 2,500 tons daily. At one point'in the.dis- 40 trict there is a stock pile of this material which is estimated to coiitain more, tli'anpnea million tons and stock piles containing hundreds of thousandsof tons may be found throughout the iron and steel districts of the United States.-. Many attempts have been made to utilize thismaterial, but it is',:'-.I believe, 'admittedgenerally by experts in this art that the problem is today unsolved. These attempts have'mainly been confined to briqueting or sintering the material. Both these methods require expensive preliminary concentration, and the expense f-installation and operation of the necessary 'appara tus is too great to renderthe methods prof; itable. Briqueting requires the use of some Specification of Letters Patent.

Application filed J u1y'24, 1913. Serial No.'780,949.

[must be added.

bonding agent to hold the particles together;

Patented Dec. 16, 1913.

and when the briquet becomes heated in'the urnace in an attempt to smelt it, the bonding agent is destroyed; the particles are then reduced to dust before they can be melted, and a greater or less percentage of such particles is again carried over'by the blast'and must be recaught and rebriqueted. If the particles be fused, or partly fused, as in the Griindahl process, the percentage of loss is still high, and the expense of the in- 'stallation .and operation of the necessary plant is increased, y I

. When sintering is resorted to, the coke in the flue dust must be eliminated, or,at least reduced to about two per cent. before it can be sintcred, and thereisthe same heavy percentage of loss. Furthermore, to the cost of sintering or briqueting the cost of resmelting My invention provides a' very simple and etficient method for utilizing this material in a practical and economical manner, with very little, if any, increased cost-for plant installation and operation. It obviates the necessity for preliminary concentration; it

enables the coke'and limestone contained in the'dust to be beneficiallyutilized; and has many other advantages which are hereinafter described.

Inmy. Patent No. 900,467, of'October 6th,

1908, I have described and claimed a method of recovering practically all thevalues con- .taincd in" fines, flue dust and concentrates in treating zincy copper concentrates and" fines. I have now discovered that a similar method may be applied to the utilization of irjon-blast-furn'ace fine dust and fines. For this purpose'I use a bath of molten pig iron, preferably directly as it is drawn from the furnace, -as the holding medium for the ma ter ial under treatment.- I' mingle this material in the moltenbath of'pig iron preferably to a point short of solidification, in any suitable'm'ixingdevicefan'd then pass them in this-mixed or mingled condition either to the. pig-bed: to 'apig molding machine; to a mixing tank; ordirectly, in a molten condition, to Bessemer coni'rerters; to open hearth or Talbot furnaces; or to electric furnaces, in any of which the refining process is con. tinued to the finalstage. may also effect the mixing directly in the'furnace, as for instance in an: open hearth furnace.

In carrying out my invention, the heavy -1nolten pig'iron is preferably allowed to drop, say from four to six feet,-o r such a distanceas will produce a suitable vortex 1 0 in the bath-which is contained in the mixing vessel. A vortex of about fifteen inches in depth can be maintained by a drop of about six feet. The flue dust material is then discharged by suitable means, some distance within this vortex, the material being al-' lowed toflow in a steady stream to the bottom of the vortex, and the low being so regulated thatt-hematerial' will not accumulate to adepth of. more thanabout five inches at .20 the bottom of the vortex. I do not, however,

' limit myself to this particular. mode of mixing. It has the advantage, however, that it 'does not permit anyof the particles of the material tb escape; but, on the contrary, the '25 heavy falling liquid bathv steadily carries fere with its proper iiow into the mixing.

bath; and it may. also be dried,'if necessary, so as to make it flow more freely.

Some fiue dust contains impurities and Q) very lean substances which will yield little i or no value. Ifdesired, these may be submitted to a suitable preliminary concentration process; This, however, is purely commercial question, depending on whether 45. or not this preliminary concentration is profitable for the particular material in question.

I do not recommend that'pig iron intended to -be simply remelted for foundry and' similar purposes be used for the pur-' pgse herein contemplated, although it may within the broad scope of my invention and claims.

I also do not limit myself to the flow. of molten iron from a blast furnace as the original' source of supply; Any molten metal fromany source may be used, in any desired manner. From an economical standpoint, it is preferred that eaclz separate blast furnace recover the values from its own roduction of flue dust and ore s as rapi ly as these be made, and preferably with each cast. When, however, the furnace is enga ed solely in makin foundry irons, or'iron ti at is intended sole y for re-melting, it may be preferable to arrange for the utilization of the fine dust in connection with the pig iron from other furnaces, or by mingling it in molten steel.

In Fig. l ofthe accompanying drawings, I have illustrated, largely diagrammatically, an arrangement of apparatus which may be employed to enable each furnace to take care of its own flue dust product. In this figure, the numeral 2 designates a portion of an ordinary blast furnace having the usual tapout 3. A designates the body of molten metal and B'the body of molten slag above the metal. fl is a forehearth or other receiving vessel into which themolten metal flows 0 from the tap-out, and through a' sufiicient distance to create a vortex such as indicated at 5 in said vessel. 6 is a bin or receptacle of any suitable character, to which t-he flue dust or the lines are supplied, and from 5 which it flows through the pipe 7 into the vorten 5. This pipe is preferably provided with a'controlling valve 8, by'which the flow can be regulated; and it may also be conveniently made in telescopic sections with suitable means, such as the cord. and pulley 9, for moving one of the sections-upon the other to properly adjust the.point of dis-- charge at the lower section.

In Fig. 2 I have shown apparatus which 5 may be used for c'arryin' out my improved 1 method in connection wit an ordinary open hearthfurnace. Inthis figure, the numeral 10 indicates the hearth portion of the furnace, which is shown as being supplied-with 10o molten pig iron from a ladle 11. 12 designates the pipe through whichthe flue dust and fines are being dischar ed -into-the-run'-.

'way 13. In this manner t e dust and pig iron are thoroughly-commingled in entering the furnace. i As above stated, the mixing operation can be carried out in various other ways. The

impurities contained in the flue 'dust are not detrimental, butare in eii'ect to aconsiderable extent useful, since they consist largely of coke and limestone, and "the coke'is useful by reason of its fuel values,- and the limestone by reason of its act-ion as at-flux.

' Ordinary coke pig iron used in the manufac- 115.

ture of steel contains approximately 28 per cent. of impurities which must be'eliminated in making steel.

The flue dust contains approximately 30' per cent. of pure iron, nearly-7O percent. of

coke particles, and'a small p'e'rcenta e of limestone, all of which are parts 0 the original furnace charge. In my pre'sent-inmention all of these are useful, as above ex? plained, and consequently the percentage of 126 actual impurities added'to the 28 per cent.

already existing in the pig iron itself, is infinitesimal, and adds nothmg to the cost of Moitenpig iron can be made to take up 130 -jecting the mixture to a iron-blast-furnace flue dust,

flue dust and fines in the manner described -in suificient quantities to not only take care naces, which consists in introducing the dust and fines into a sufficient body of molten iron or steel to cause them to be enveloped by the iron or steel and thoroughly mingled therewith; substantially as described.

2. The herein described method of utilizing the flue dust and fines from iron blast furnaces, which consists in mingling the flue dust or fines with molten metal to a point short of solidification, and then subrefining action; substantially as described. a

3. The herein described method of utilizing flue dust and fines in iron blast furnaces, which consists in flowing molten iron into a receiving vessel, and at the same time introducing into the molten, metal the flue dust and fines; substantially, as described.

4. The herein described method of utilizing the flue dust and fines of iron blast furnaces, which consists in first subjecting the material to a preliminary separating operation, and then introducing it into-' a suflicient body of molten iron or steel to cause the dust to be enveloped by the iron or stel and thoroughly mingled therewith; substantially as described.

5. The lizing the flue dust and fines of iron blast furnaces, which consists in introducing the dust and fines within a body of molten metal while the metal is in a condition of movement by causing oped by the molten metal, and thereby effect a thorough mingling of the dust and fines with the molten metal; substantially as described.

6. The method of recovering values from ore fines, and

enveloped by herein described method of uti-' the material to be envel which consists in introducing into a sufficient'body of molto cause the material to be the iron or steel and thoroughlymingled therewith, and utilizing the particles of carbon and lime contained in such material as fuel and flux elements, respectively, in the treatment of the iron; substantially as described.

7. The method of recovering values from iron-blast-furnace flue-dust; ore fines, and concentrates, which consists in introducing such material into a fallingst-ream of molten pig iron ment in the process of making steel; substantially as described.

'8. The method of recovering values from iron bl'ast furnace flue dust, ore fines and concentrates, which consists in pouring hot metal from one vessel into a second vessel to produce a vortex in the hot metal in the second vessel, and simultaneously introducconcentrates, such mater1al ten pig iron in such material into the vortex to draw b tially as described. 9. The method the material into the molten mass; substana molten iron or steel and hold it in suspen sion therein for subsequent treatment; substantially as describe In testimony whereof, I have hereunto set my hand.

J RALPH BAGGALE Y; lVit-nesses Gno. H. PARMELEE, H. M. Oonwnm Copies of this intent may be obtained for five cents each, by addressing the Bommlsstoner of Patents,

' Washington, D. G. m

preparatory to further treatmethod of utilizing flue dust and of recovering values from iron blast furnace flue dust, ore fines and, 

